All-electric all-semiconductor spin field-effect transistors

Two quantum point contacts are used to respectively inject and detect spins by purely electrical means in an all-semiconductor spin transistor. The spin field-effect transistor envisioned by Datta and Das1 opens a gateway to spin information processing2,3. Although the coherent manipulation of electron spins in semiconductors is now possible4,5,6,7,8, the realization of a functional spin field-effect transistor for information processing has yet to be achieved, owing to several fundamental challenges such as the low spin-injection efficiency due to resistance mismatch9, spin relaxation and the spread of spin precession angles. Alternative spin transistor designs have therefore been proposed10,11, but these differ from the field-effect transistor concept and require the use of optical or magnetic elements, which pose difficulties for incorporation into integrated circuits. Here, we present an all-electric and all-semiconductor spin field-effect transistor in which these obstacles are overcome by using two quantum point contacts as spin injectors and detectors. Distinct engineering architectures of spin–orbit coupling are exploited for the quantum point contacts and the central semiconductor channel to achieve complete control of the electron spins (spin injection, manipulation and detection) in a purely electrical manner. Such a device is compatible with large-scale integration and holds promise for future spintronic devices for information processing.